Cash flow statement supplementary information - Text Details (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flow statement supplementary information - Text Details (Detail) [Line Items]
Purchase of financial instruments, classified as investing activities	€ (177)	€ (295)	€ (128)
Net cash inflow from non-current financial assets	€ 43	€ 36	€ 39

The cash outflow for the purchase of financial instruments. [Refer: Financial instruments, class [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2017-01-01
-Paragraph 16
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_16&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_PurchaseOfFinancialInstrumentsClassifiedAsInvestingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration